Mar 31, 2009

Amplification of the North American “Dust Bowl” drought through human-induced land degradation

Benjamin I. Cook, Ron L. Miller, Richard Seager
Proceedings of the National Academy of Sciences
  • States that the Dust Bowl drought of the 1930s was highly unusual for North America, deviating from the typical pattern forced by La Niña with the maximum drying in the central and northern Plains, warm temperature anomalies across almost the entire continent, and widespread dust storms
  • States that general circulation models (GCMs), forced by sea surface temperatures (SSTs) from the 1930s, produce a drought, but one that is centered in southwestern North America and without the warming centered in the middle of the continent
  • Shows that the inclusion of forcing from human land degradation during the period, in addition to the anomalous SSTs, is necessary to reproduce the anomalous features of the Dust Bowl drought
  • The degradation over the Great Plains is represented in the GCM as a reduction in vegetation cover and the addition of a soil dust aerosol source, both consequences of crop failure
  • Vegetation reductions explain the high temperature anomaly over the northern U.S., and the dust aerosols intensify the drought and move it northward of the purely ocean-forced drought pattern